Air-jet type spinning device

Abstract

An air-jet type spinning device comprising at least one injection hole configured to introduce a flow of compressed air in a spinning chamber. A fibre feeding device facing the spinning chamber feeds the fibres in the spinning chamber. A spinning spindle is at least partially inserted in the spinning chamber and fitted with a spinning channel for the transit of yarn obtained from the fibres.

The invention claimed is: 
     
       1. Air-jet type spinning device comprising
 a body at least partially hollow, which delimits a cylindrical spinning chamber, the body comprising at least one injection hole configured to inject a flow of compressed air into said spinning chamber, 
 a fibre feeding device, facing said spinning chamber so as to feed the fibres into the spinning chamber, 
 the fibre feeding device comprising a fibre feeding channel having a first straight section leading, at a shoulder, into a pre-chamber facing and communicating with said spinning chamber, 
 a spinning spindle at least partially inserted in the spinning chamber and fitted with a spinning channel for the transit of yarn obtained from said fibres, the spinning channel having a main axis which defines a spinning direction, and having a front input for the introduction of the yarn in said spinning channel, 
 
       wherein a diameter of the spinning chamber, measured relative to a cross-section plane perpendicular to said main axis, is between 5.6 and 7.4 mm, and, 
       wherein the distance between the at least one injection hole and the front input, measured parallel to the spinning direction, is greater than or equal to 0.3 mm, the injection hole being arranged upstream of the front input. 
     
     
       2. Air-jet type spinning device according to  claim 1 , wherein the spinning spindle has, overall, a truncated cone shape with a circular and axial symmetric cross-section with respect to said spinning direction, the spinning spindle tapering towards the front input. 
     
     
       3. Air-jet type spinning device according to  claim 1 , wherein said spinning spindle has an inlet diameter, at said front input, between 47% and 61% of the diameter of the spinning chamber. 
     
     
       4. Air-jet type spinning device according to  claim 3 , wherein said inlet diameter is between 3.2 mm and 3.9 mm. 
     
     
       5. Air-jet type spinning device according to  claim 1 , wherein the spinning spindle has a truncated cone shape, wherein an average diameter of said spinning spindle, at an intermediate height of the spinning spindle, is equal to 1.1-1.3 times an inlet diameter of the spinning spindle, at said front input. 
     
     
       6. Air-jet type spinning device according to  claim 5 , wherein a bottom diameter of the spinning spindle, opposite the front input, is equal to 1.1-1.3 times said average diameter. 
     
     
       7. Air-jet type spinning device according to  claim 1 , wherein the first straight section of the fibre feeding channel, with respect to a cross-section plane passing through a median plane of the first straight section and a central axis of the feeding device, is inclined with respect to said central axis. 
     
     
       8. Air-jet type spinning device according to  claim 1 , wherein the first straight section, with respect to a cross-section plane passing through a median plane of said first straight section and a central axis of the fibre feeding device, has a truncated-conical cross-section diverging towards the spinning chamber. 
     
     
       9. Air-jet type spinning device according to  claim 1 , wherein said first straight section, with respect to a cross-section plane passing through a median plane of the first straight section and a central axis of the fibre feeding device, is delimited by an external wall inclined with respect to the central axis by an external angle between 2° and 3.75°. 
     
     
       10. Air-jet type spinning device according to  claim 1 , wherein said first straight section, with respect to a cross-section plane passing through a median plane of the first straight section and a central axis of the fibre feeding device, is delimited by an inner wall inclined with respect to the central axis by an inner angle between 3.5° and 5.5°. 
     
     
       11. Air-jet type spinning device according to  claim 1 , in which said at least one injection hole is arranged upstream of the front input of the spinning spindle, along said spinning direction. 
     
     
       12. Air-jet type spinning device according to  claim 1 , wherein said at least one injection hole is placed at a distance from the shoulder between 2.4 and 3.5 mm. 
     
     
       13. Air-jet type spinning device according to  claim 1 , wherein the spinning chamber is delimited at least partially by an outer side wall, opposite the spinning spindle, wherein on said outer side wall at least one thread is made, wherein said at least one injection hole is oriented so as to direct the jet of compressed air towards the at least one thread so as to be guided and oriented by the latter. 
     
     
       14. Air-jet type spinning device according to  claim 13 , wherein said at least one thread is a helical thread. 
     
     
       15. Air-jet type spinning device according to  claim 13 , wherein the spinning device comprises at least two injection holes that direct compressed air at two separate emission points, said emission points being diametrically opposite each other and sending jets of compressed air in opposite directions to each other. 
     
     
       16. Air-jet type spinning device according to  claim 13 , wherein said thread has a curved or semi-circular geometry cross-section with a radius between 0.25 mm and 2 mm. 
     
     
       17. Air-jet type spinning device according to  claim 13 , wherein said thread is inclined at a helix angle of between 5° and 15°. 
     
     
       18. Air-jet type spinning device according to  claim 13 , wherein the pitch of said thread is between 1.5 mm and 4 mm. 
     
     
       19. Air-jet type spinning device according to  claim 1 , wherein the fibre feeding device comprises a needle, at least partially penetrated in said spinning chamber and axially counterposed to said front input, so as to create a guide for the fibres being spun.